As of December 2003 Flash 7 player penetration rate had reached 28.9% in USA.

Bottom line:
( taken from blog of Emmy Huang, Product Manager of the Flash Player )
This is 56% faster than Flash Player 6 and Flash Player 7 in the first quarters of those releases.
And, based on the server stats from our hosting company, Akamai, Flash Player 8 has been downloaded over 1.4 billion times since the September launch